Information processing apparatus, system, non-transitory computer-readable storage medium with executable program stored thereon, and method

ABSTRACT

An information processing apparatus includes sound selection means for selecting a sound to be outputted from a sound candidate group, sound output means for outputting the selected sound when an output condition is satisfied, sleep state estimation means for estimating a sleep state of a user based on a result of measurement by a sensor that measures body motion of the user, hours-of-sleep calculation means for calculating hours of sleep of the user based on the estimated sleep state of the user, and addition means for adding a new sound to the sound candidate group based on the calculated hours of sleep of the user.

This nonprovisional application claims priority to Japanese PatentApplication No. 2021-150869 filed with the Japan Patent Office on Sep.16, 2021, the entire contents of which are hereby incorporated byreference.

FIELD

The present disclosure relates to an information processing apparatusand a system that estimate a sleep state, a medium having a programdirected to the information processing apparatus stored thereon, and amethod performed in the information processing apparatus.

BACKGROUND AND SUMMARY

An apparatus that more diversifies messages and characters to beoutputted in response to an operation by a user has been known. Forexample, an alarm clock that performs processing for increasing anempirical value when an operation to stop an alarm is performed at thetime of sounding of the alarm or an operation to stop the alarm isperformed at the time of sounding again of the alarm once stopped by asnooze function and processing for increasing variation in messages tobe outputted as a prescribed empirical value is attained and a level israised has been disclosed.

In the conventional apparatus described above, estimation of a sleepstate of a user is not assumed. The present disclosure is directed to ascheme that allows various sounds to be provided to a user based on asleep state of the user.

An exemplary embodiment provides an information processing apparatusthat includes a memory storing a computer-readable program and one ormore processors. The one or more processors, when executing thecomputer-readable program, perform selecting a sound to be outputtedfrom a sound candidate group, outputting the selected sound when anoutput condition is satisfied, estimating a sleep state of a user basedon a result of measurement by a sensor that measures body motion of theuser, calculating hours of sleep of the user based on the estimatedsleep state of the user, and adding a new sound to the sound candidategroup based on the calculated hours of sleep of the user.

According to this configuration, the information processing apparatuscalculates the hours of sleep of the user based on the estimated sleepstate of the user and adds the new sound to the sound candidate groupbased on the calculated hours of sleep of the user. Therefore, in orderto increase variation in sounds to be outputted, the user has to have asleep. In other words, the user can be motivated to have more sleep inassociation with output of the new sound.

The adding the new sound to the sound candidate group may be based on acumulative total of the calculated hours of sleep of the user. Accordingto this configuration, since the new sound is added based on thecumulative total of the hours of sleep of the user, the user can bemotivated to have a sleep as long as possible.

The adding the new sound to the sound candidate group may include addingthe new sound when a cumulative total of the calculated hours of sleepof the user reaches a prescribed threshold value. According to thisconfiguration, a developer can freely adjust at which timing a sound isto be added.

The prescribed threshold value may include a plurality of thresholdvalues. In this case, the adding the new sound to the sound candidategroup may include adding the new sound each time the cumulative total ofthe calculated hours of sleep of the user reaches at least one of theplurality of threshold values. According to this configuration, a soundcan be added stepwise with the use of the plurality of threshold values.

As compared with a difference between a first threshold value includedin the plurality of threshold values and a second threshold valuelargest next to the first threshold value, a difference between thesecond threshold value and a third threshold value largest next to thesecond threshold value may be larger. According to this configuration,since a sound is soon added immediately after start of use, the user canuse the information processing apparatus with enjoyment. In addition,since a time period until addition of all sounds can be longer, the usercan use the information processing apparatus with enjoyment for a longerperiod of time.

The one or more processors, when executing the computer-readableprogram, may further perform, after the user wakes up, evaluation basedon the calculated hours of sleep immediately before. In this case, theadding the new sound to the sound candidate group may include adding thenew sound based on a result of the evaluation. According to thisconfiguration, by evaluating after wake-up of the user, the hours ofsleep of the user based on the calculated hours of sleep immediatelybefore, a condition for adding the new sound can appropriately bedetermined.

The adding the new sound to the sound candidate group may includedetermining the new sound to be added by a draw. According to thisconfiguration, since the user is unable to expect the new added sound,the user can be given expectation and can more strongly be motivated tohave a sleep.

A probability that each of sounds that have not yet been added to thesound candidate group is determined as the new sound may be equal.According to this configuration, since a sound that has not yet beenadded to the sound candidate group is selected at the same probabilityand added to the sound candidate group, variation in sounds to beoutputted can be increased without any bias being given to a specificsound.

The one or more processors, when executing the computer-readableprogram, may further perform determining whether or not to activateprocessing for adding the new sound to the sound candidate group basedon the calculated hours of sleep of the user. In this case, the addingthe new sound to the sound candidate group may include adding the newsound to the sound candidate group when processing for adding the newsound is activated. According to this configuration, since it is notnecessarily the case that the new sound is added without fail based onthe calculated hours of sleep of the user, the user can be givenexpectation. Since determination not to add the new sound may be made,the user can be motivated to have a sleep.

The selecting a sound may include selecting a sound to be outputted fromthe sound candidate group by a draw. According to this configuration,since a sound to be outputted from an output apparatus is varied by thedraw, the user can be given expectation.

A probability that a sound included in the sound candidate group isselected as a sound to be outputted by the draw may be higher as thehours of sleep of the user immediately before the output condition issatisfied are longer. According to this configuration, since a soundthat is more likely to be outputted is varied based on the hours ofsleep of the user, the user can be motivated to have a sleep for outputof more types of sounds.

The selecting the sound may include selecting, when the calculated hoursof sleep of the user exceed prescribed hours, a sound to be outputtedfrom among more sounds than when the calculated hours of sleep of theuser do not exceed the prescribed hours. According to thisconfiguration, since the output apparatus outputs more types of soundsas the hours of sleep are longer, the user can be motivated to have asleep.

A probability that at least one sound included in the sound candidategroup is selected as the sound to be outputted may be higher as thehours of sleep of the user are longer. According to this configuration,since a probability of selection of a specific sound included in thesound candidate group remains low unless the hours of sleep are long,the user can be motivated to have a sleep.

A probability that each of sounds included in the sound candidate groupis selected as the sound to be outputted may be equal. According to thisconfiguration, sounds included in the sound candidate group can evenlybe outputted.

A sound more recently added to the sound candidate group may be higherin probability of selection as the sound to be outputted. According tothis configuration, since a newly added sound is more likely to beoutputted as the user has a sleep, the user can more reliably feel aneffect of having a sleep.

The selecting a sound may include selecting the sound to be outputted ina predetermined order from the sound candidate group. According to thisconfiguration, since sounds included in the sound candidate group aresequentially outputted, each sound can reliably be heard by the user.

A sound may be added to the sound candidate group in a unit of a soundset composed of a plurality of sounds. In this case, the selecting asound may include selecting sounds to be outputted in the unit of thesound set and determining a sound to be outputted from among the soundsincluded in the selected sound set. According to this configuration,since switching of output between sounds included in the selected soundset can be made, variation in sounds to be outputted can be increased.

The selecting the sound may include selecting as a sound to be outputtednext, a sound different from a previously selected sound from amongsounds included in the sound set when a switching condition is satisfiedafter output of the sound is started. According to this configuration, asound included in the selected sound set can be heard by the user.

The switching condition may include a condition that a duration ofoutput of a sound that is currently being outputted reaches a prescribedduration. According to this configuration, since switching to output ofa next sound is made when the same sound is outputted for the durationof output, the user can enjoy various sounds.

The one or more processors, when executing the computer-readableprogram, may further perform temporarily stopping output of the sound.In this case, the switching condition may include temporary stop ofoutput of the sound. According to this configuration, when output of thesound is temporarily stopped, a sound to be outputted next is differentfrom the previous sound. Therefore, the user can enjoy various sounds.

The outputting the sound may include outputting again the sound, outputof which has ended, when a condition for output again is satisfiedwithin a prescribed period after end of output of the sound. Accordingto this configuration, even when the user missed a sound outputted atthe time when the output condition was satisfied or when the user wasunable to sufficiently hear the sound, the user can hear the same soundlater.

The one or more processors, when executing the computer-readableprogram, may further perform sensing a shake that occurs in theinformation processing apparatus. In this case, the condition for outputagain may include sensing of the shake of the information processingapparatus. According to this configuration, since the sound is outputtedagain as the user shakes the information processing apparatus, the usercan hear the sound again by an easy operation.

In the information processing apparatus, the sensor may be anacceleration sensor. According to this configuration, the sleep state ofthe user can be estimated with the use of the acceleration sensor.

The one or more processors, when executing the computer-readableprogram, may further perform obtaining a sound from another informationprocessing apparatus different from the information processingapparatus. According to this configuration, variation in soundsoutputted from the output apparatus can be increased by obtaining asound from another information processing apparatus.

Another exemplary embodiment provides a system including a soundgenerator. The system includes a sound selection module that selects asound to be outputted from a sound candidate group, a sound outputmodule that outputs the selected sound from the sound generator when anoutput condition is satisfied, a sleep state estimation module thatestimates a sleep state of a user based on a result of measurement by asensor that measures body motion of the user, an hours-of-sleepcalculation module that calculates hours of sleep of the user based onthe estimated sleep state of the user, and an addition module that addsa new sound to the sound candidate group based on the calculated hoursof sleep of the user.

Another exemplary embodiment provides a non-transitory computer-readablestorage medium with an executable program stored thereon. The programcauses a computer configured to output a sound to perform selecting asound to be outputted from a sound candidate group, outputting theselected sound when an output condition is satisfied, estimating a sleepstate of a user based on a result of measurement by a sensor thatmeasures body motion of the user, calculating hours of sleep of the userbased on the estimated sleep state of the user, and adding a new soundto the sound candidate group based on the calculated hours of sleep ofthe user.

Another exemplary embodiment provides a method performed in aninformation processing apparatus configured to output a sound. Themethod includes selecting a sound to be outputted from a sound candidategroup, outputting the selected sound when an output condition issatisfied, estimating a sleep state of a user based on a result ofmeasurement by a sensor that measures body motion of the user,calculating hours of sleep of the user based on the estimated sleepstate of the user, and adding a new sound to the sound candidate groupbased on the calculated hours of sleep of the user.

The foregoing and other objects, features, aspects and advantages of thepresent disclosure will become more apparent from the following detaileddescription of the present disclosure when taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an exemplary illustrative non-limiting drawing illustratingan overall configuration of a system according to the presentembodiment.

FIG. 2 shows an exemplary illustrative non-limiting drawing illustratinga hardware configuration of an output apparatus in the system accordingto the present embodiment.

FIG. 3 shows an exemplary illustrative non-limiting drawing illustratingsound addition processing according to the present embodiment.

FIGS. 4A and 4B show exemplary illustrative non-limiting drawingsillustrating sound selection and output processing according to thepresent embodiment.

FIG. 5 shows an exemplary illustrative non-limiting drawing illustratinga functional configuration of the output apparatus according to thepresent embodiment.

FIG. 6 shows an exemplary illustrative non-limiting drawing illustratingan exemplary sleep state estimated by the output apparatus according tothe present embodiment.

FIG. 7 shows an exemplary illustrative non-limiting drawing illustratingan exemplary condition used in the sound addition processing accordingto the present embodiment.

FIG. 8 shows an exemplary illustrative non-limiting drawing illustratingexemplary sound addition processing according to the present embodiment.

FIG. 9 shows an exemplary illustrative non-limiting flowchartillustrating a processing procedure in the sound addition processingaccording to the present embodiment.

FIG. 10 shows an exemplary illustrative non-limiting flowchartillustrating another processing procedure in the sound additionprocessing according to the present embodiment.

FIG. 11 shows an exemplary illustrative non-limiting flowchartillustrating a processing procedure in the sound selection and outputprocessing according to the present embodiment.

FIG. 12 shows an exemplary illustrative non-limiting drawingillustrating an exemplary method of determining selectable sounds in theoutput apparatus according to the present embodiment.

FIG. 13 shows an exemplary illustrative non-limiting drawingillustrating an exemplary method of selecting a sound in the outputapparatus according to the present embodiment.

FIG. 14 shows an exemplary illustrative non-limiting drawingillustrating another exemplary method of selecting a sound in the outputapparatus according to the present embodiment.

FIG. 15 shows an exemplary illustrative non-limiting drawingillustrating exemplary processing for changing a sound in the outputapparatus according to the present embodiment.

FIG. 16 shows an exemplary illustrative non-limiting flowchartillustrating a processing procedure for output again of a soundaccording to the present embodiment.

DETAILED DESCRIPTION OF NON-LIMITING EXAMPLE EMBODIMENTS

The present embodiment will be described in detail with reference to thedrawings. The same or corresponding elements in the drawings have thesame reference characters allotted and description thereof will not berepeated.

A. Exemplary Overall Configuration

An exemplary overall configuration of a system 1 according to thepresent embodiment will initially be described. FIG. 1 is a schematicdiagram showing an overall configuration of system 1 according to thepresent embodiment.

Referring to FIG. 1 , system 1 includes an output apparatus 100 by wayof example of an information processing apparatus configured to output asound. Output apparatus 100 may be configured as a kind of an alarmclock.

System 1 may further include a portable terminal 200 that can exchangedata by wireless or wired communication with output apparatus 100.Portable terminal 200, however, is not an essential feature.

Portable terminal 200 may be an information processing apparatusconfigured to execute any applications. Portable terminal 200 isimplemented, for example, by a smartphone, a tablet, a personalcomputer, or a game device. Portable terminal 200 can also transmit oneor more sounds to output apparatus 100 in accordance with an operationby a user.

When output apparatus 100 and portable terminal 200 are connected toeach other through wireless communication, for example, any wirelessscheme such as Bluetooth®, ZigBee®, wireless LAN (IEEE 802.11), orinfrared communication can be adopted.

B. Exemplary Hardware Configuration of Output Apparatus 100

An exemplary hardware configuration of output apparatus 100 of system 1according to the present embodiment will now be described.

FIG. 2 is a schematic diagram showing a hardware configuration of outputapparatus 100 in system 1 according to the present embodiment. Referringto FIG. 2 , output apparatus 100 represents an exemplary computer, andincludes, as its main components, one or more processors 102, a memory104, a storage 106, a real time clock (RTC) 110, an acceleration sensor112, a display unit 114, a vibrator 116, a sound generator 118, awireless communication unit 120, and an operation unit 122. Thesecomponents are electrically connected to one another through a bus 124.

Processor 102 is a processing entity (processing means) for performingprocessing provided by output apparatus 100. Processor 102 performsprocessing as will be described later by reading a system program 108stored in storage 106 and developing the system program on memory 104.System program 108 includes an instruction code for performingprocessing as will be described later.

Memory 104 is a storage device that can be accessed by processor 102,and it is implemented, for example, by a volatile storage device such asa dynamic random access memory (DRAM) or a static random access memory(SRAM). Storage 106 is implemented, for example, by a non-volatilestorage device such as a flash memory.

In storage 106, sound data 130 and a sound management table 140 arestored in addition to system program 108.

RTC 110 manages time and provides information indicating current time toprocessor 102 or the like.

Acceleration sensor 112 is a sensor that detects motion produced inoutput apparatus 100 and used for estimation of a sleep state of a useras will be described later.

Display unit 114 is a component that visually provides information to auser, and it is implemented, for example, by a light emitting diode(LED) or a liquid crystal display.

Vibrator 116 provides vibration to a user.

Sound generator 118 is a component that provides any auditoryinformation to a user, and it is implemented, for example, by a speakeror a buzzer.

Wireless communication unit 120 exchanges data with portable terminal200 through a wireless signal.

Operation unit 122 is a component that accepts an operation from a user,and it is implemented by such a device as a push button, a controllever, a touch panel, a mouse, and the like.

Processing performed in output apparatus 100 may be performed byexecution of a program by the processor, or a part or the entiretythereof may be implemented by hard-wired circuitry such as anapplication specific integrated circuit (ASIC) or a field programmablegate array (FPGA).

The term “processor” herein encompasses not only a normal meaning of aprocessing circuit that performs processing in accordance with aninstruction code described in a program, such as a central processingunit (CPU), a micro processing unit (MPU), or a graphics processing unit(GPU), but also hard-wired circuitry such as an ASIC or an FPGA. In thehard-wired circuitry such as an ASIC or an FPGA, a circuit correspondingto processing to be executed is formed in advance. Furthermore, the“processor” herein also encompasses circuitry in which a plurality offunctions are integrated, such as a system on chip (SoC).

C. Overview of Processing

Overview of processing in output apparatus 100 according to the presentembodiment will now be described. Output apparatus 100 performs soundaddition processing for adding a new sound to a sound candidate groupbased on hours of sleep of a user and sound selection and outputprocessing for selecting a sound to be outputted from a sound candidategroup and outputting the selected sound when an output condition issatisfied.

“Hours of sleep” herein means a length of time for which a user isasleep and/or is estimated to be asleep. A unit for calculating “hoursof sleep” is arbitrarily defined, for example, as hour, minute, second,and so on.

Output apparatus 100 according to the present embodiment can output aplurality of sounds. In the description below, an example in whichsounds are categorized based on an attribute “mood” is shown.Specifically, a plurality of sounds corresponding to a plurality ofmoods, respectively, are prepared. By preparing sounds in considerationof such “moods”, a user can feel output apparatus 100 as if it were a“living creature.” The user thus tends to feel an attachment to outputapparatus 100. Any type of sounds may be prepared and outputted.

The “sound” herein collectively refers to an expression that a user canperceive by the sense of hearing. The term “sound” means a unit ofoutput from output apparatus 100, and whether or not a “sound” is to beoutputted from output apparatus 100 is managed for each “sound”.

“Sound data” herein means music data for realizing output of a sound.For example, the sound data is composed of data coded under a knownmusic format.

A “sound set” herein means a set of a plurality of “sounds”. In otherwords, the “sound set” is composed of a plurality of “sounds”. Forexample, a “sound set” may be composed of a plurality of “sounds” commonor similar in attribute.

A “sound candidate group” herein means a set of sounds output of whichfrom output apparatus 100 is logically permitted. A plurality of soundsare prepared in advance for output apparatus 100, and output apparatus100 changes one or all of the plurality of these prepared sounds to anavailable state based on hours of sleep of a user. A sound may be addedto the “sound candidate group” in a unit of a sound set.

FIG. 3 is a schematic diagram for illustrating sound addition processingaccording to the present embodiment. Referring to FIG. 3 , soundmanagement table 140 includes information on a prepared sound 132 andinformation as to whether or not each sound 132 has already been addedto a sound candidate group 134.

For output apparatus 100, for example, sounds 132-1 to 132-7 (which mayalso collectively be referred to “sound 132” below) corresponding torespective moods are prepared. Each sound 132 is brought incorrespondence with specific sound data 130.

An element in the sound candidate group may be a sound set composed of aplurality of sounds 132, rather than an individual sound 132. One ormore sounds 132 included in the sound set each correspond to the same“mood”. Details of the sound set will be described later.

In an initial state, at least one of the plurality of sounds 132 isavailable. In other words, at least one sound 132 has already been addedto sound candidate group 134.

Output apparatus 100 adds at least one of sounds 132 that have not yetbeen added to sound candidate group 134 among sounds 132 prepared inadvance to sound candidate group 134, based on hours of sleep of theuser. Details of processing (sound addition processing) for adding sound132 to sound candidate group 134 will be described later.

FIGS. 4A and 4B are schematic diagrams for illustrating sound selectionand output processing according to the present embodiment. Referring toFIG. 4 , output apparatus 100 selects sound 132 to be outputted fromsound candidate group 134. Output apparatus 100 outputs the selectedsound when an output condition is satisfied.

Sound candidate group 134 shown in FIG. 4A includes sounds 132-1, 132-5,and 132-6. Therefore, output apparatus 100 selects one sound 132 fromthese three sounds 132.

Sound candidate group 134 shown in FIG. 4B is in a state where sound132-3 has been added to sound candidate group 134 by sound additionprocessing. In other words, sound candidate group 134 includes sounds132-1, 132-3, 132-5, and 132-6. Therefore, output apparatus 100 selectsone sound 132 from these four sounds 132.

Output apparatus 100 may perform only one of sound addition processingand sound selection and output processing.

D. Exemplary Functional Configuration

An exemplary functional configuration of output apparatus 100 accordingto the present embodiment will now be described.

FIG. 5 is a schematic diagram showing an exemplary functionalconfiguration of output apparatus 100 according to the presentembodiment. Referring to FIG. 5 , output apparatus 100 includes, as itsmain functional components, a sleep state estimation module 150, anhours-of-sleep calculation module 152, an addition module 154, an outputmanagement module 156, a sound selection module 158, a sound outputmodule 160, and a sound obtaining module 162. These functionalcomponents are typically implemented by execution of system program 108by processor 102 of output apparatus 100.

Sleep state estimation module 150 estimates a sleep state of a userbased on a result of measurement by a sensor that measures body motionof the user. For example, acceleration sensor 112 measures body motionof the user. Typically, output apparatus 100 is arranged on bedclothes(a mattress or the like) on which the user lies, so as to detect bodymotion produced by the user during sleep.

The sleep state estimated by sleep state estimation module 150 mayinclude, for example, a sleeping state and an awake (awakened) state.The sleeping state may further be divided into REM sleep and non-REMsleep, or depth of sleep may be outputted. Sleep state estimation module150 may estimate the sleep state and output a result of estimation onlywhen body motion of the user is successfully appropriately measured. Forexample, when the user is not present within a range of measurement orwhen the user is not ready to lie on bed, output of a result ofestimation of the sleep state may not be provided.

Without being limited to acceleration sensor 112, another sensor may beused to measure body motion of the user and to estimate the sleep stateof the user. Any known algorithm can be adopted as an algorithm forestimating the sleep state of the user.

Hours-of-sleep calculation module 152 calculates hours of sleep of theuser based on the sleep state of the user estimated by sleep stateestimation module 150. More specifically, hours-of-sleep calculationmodule 152 integrates time periods during which the user is sleeping inthe sleep states of the user successively outputted from sleep stateestimation module 150. Hours-of-sleep calculation module 152 outputs asthe hours of sleep of the user, for example, a cumulative total of thehours of sleep (from any initial state) and/or the hours of sleep duringa prescribed most recent period (for example, twenty-four hours or oneweek).

Addition module 154 adds a new sound as the sound candidate group basedon the calculated hours of sleep of the user. In the present embodiment,by way of example, the sound candidate group is managed with the use ofsound management table 140. More specifically, in sound management table140, a plurality of identifiers are defined, and one or more pieces ofsound data 130 are associated with each identifier. Furthermore,information indicating availability is added to each of the identifiersin sound management table 140. Addition module 154 adds a new sound asthe sound candidate group by updating the information included in soundmanagement table 140 that indicates availability. Details of managementof the sound candidate group with the use of sound management table 140will be described later.

Output management module 156 determines whether or not an outputcondition has been satisfied. When output apparatus 100 is implementedas an alarm clock, output management module 156 determines whether ornot start time set in advance has come based on current time provided byRTC 110. For example, the user may be able to freely set the start timeby operating output apparatus 100 and/or portable terminal 200.

Thus, the output condition may include arrival of start time set inadvance. When the user's sleep is shallow at the time when start timeset in advance is close, the output condition may be determined as beingsatisfied.

Sound selection module 158 selects a sound to be outputted from thesound candidate group. Details of a method of selection of a sound bysound selection module 158 will be described later.

Sound output module 160 outputs the selected sound when the outputcondition is satisfied. More specifically, when output management module156 determines that the output condition has been satisfied, soundoutput module 160 reproduces sound data 130 corresponding to the soundselected by sound selection module 158. Sound generator 118 generates asound in accordance with a signal generated by reproduction of sounddata 130.

Sound obtaining module 162 obtains a sound from another informationprocessing apparatus (for example, portable terminal 200) different fromoutput apparatus 100. More specifically, sound obtaining module 162communicates with portable terminal 200 through wireless communicationunit 120 to obtain new sound data 130 and has the new sound data storedin storage 106. An entry corresponding to the sound (sound data 130)obtained from portable terminal 200 is added to sound management table140.

The sound (sound data 130) obtained from portable terminal 200 may ormay not be added to the sound candidate group immediately after it isobtained.

E. Estimation of Sleep State and Calculation of Hours of Sleep

Details of estimation of the sleep state and calculation of hours ofsleep of the user will now be described.

Sleep state estimation module 150 of output apparatus 100 estimates thesleep state of the user based on a result of measurement by the sensorthat measures body motion of the user. Typically, the result ofmeasurement by the sensor that measures body motion of the user isprovided from acceleration sensor 112. Any known algorithm can beadopted as an algorithm for estimating the sleep state of the user basedon the body motion of the user.

FIG. 6 is a schematic diagram showing an exemplary sleep state estimatedby output apparatus 100 according to the present embodiment. Referringto FIG. 6 , sleep state estimation module 150 of output apparatus 100outputs as a result of estimation of the sleep state, for example, anindicator indicating depth of sleep each time the user wakes up.

Hours-of-sleep calculation module 152 of output apparatus 100 can set aprescribed criterion value Th for the indicator indicating depth ofsleep and calculate a period during which the depth of sleep exceedscriterion value Th as the hours of sleep of the user.

The hours of sleep of the user may be accumulated from any initial stateor calculated for each prescribed most recent cycle (for example,twenty-four hours or one week).

Through the processing as described above, output apparatus 100estimates the sleep state of the user and calculates the hours of sleepof the user.

F. Sound Addition Processing

Details of the sound addition processing will now be described. In thesound addition processing, a new sound is added to the sound candidategroup based on the hours of sleep of the user.

(f1: Typical Exemplary Processing)

A cumulative total of the calculated hours of sleep of the user may beused as an exemplary condition for adding a sound. Specifically, a newsound may be added to the sound candidate group based on the cumulativetotal of the hours of sleep of the user.

FIG. 7 is a schematic diagram for illustrating an exemplary conditionused in the sound addition processing according to the presentembodiment. Referring to FIG. 7 , a threshold value table 170 defines aplurality of cumulative totals of the hours of sleep of the user beyondwhich the sound addition processing is performed.

When the cumulative total of the calculated hours of sleep of the userreaches at least one of threshold values defined in threshold valuetable 170, addition module 154 of output apparatus 100 adds a new soundto the sound candidate group. In an example shown in FIG. 7 , the soundaddition processing may be performed each time the cumulative total ofthe hours of sleep reaches each of 10 hr, 20 hr, 40 hr, 80 hr, 200 hr,500 hr, 1000 hr, A plurality of threshold values for performing thesound addition processing may thus be set. Addition module 154 of outputapparatus 100 adds a new sound to the sound candidate group each timethe cumulative total of the calculated hours of sleep of the userreaches at least one of the plurality of threshold values.

In an example where a plurality of threshold values are set, intervalsbetween adjacent threshold values may be identical to or different fromone another. In threshold value table 170 shown in FIG. 7 , theintervals between adjacent threshold values are set to graduallyincrease.

More specifically, a difference (20 hr) between the second thresholdvalue (20 hr) and the third threshold value (40 hr) included inthreshold value table 170 is larger than a difference (10 hr) betweenthe first threshold value (10 hr) and the second threshold value (20hr). This is also applicable to subsequent threshold values. By thussetting the threshold values, immediately after start of use, a sound issoon added. Therefore, the user can use the information processingapparatus with enjoyment. In addition, since time until addition of allsounds can be longer, the user can use the information processingapparatus with enjoyment for a longer period of time.

FIG. 8 is a schematic diagram for illustrating exemplary sound additionprocessing according to the present embodiment. Referring to FIG. 8 ,for example, it is assumed that sounds 132-1, 132-5, and 132-6 amongsounds 132-1 to 132-7 have been added to sound candidate group 134.

In this case, sound 132 to be added to sound candidate group 134 isdetermined from sounds 132-2, 132-3, 132-4, and 132-7 which have not yetbeen added to sound candidate group 134.

A new sound to be added to sound candidate group 134 may be determinedin a predetermined order. For example, sound 132 arranged at the top orthe end among sounds 132-2, 132-3, 132-4, and 132-7 which have not yetbeen added to sound candidate group 134 may be determined as a new soundto be added to sound candidate group 134.

Alternatively, new sound 132 to be added to sound candidate group 134may be determined by a draw. Specifically, addition module 154 of outputapparatus 100 may determine new sound 132 to be added by the draw. Forat least one sound 132, however, an order of addition thereof may bedetermined in advance, without the draw being made therefor. Forexample, sounds 132-1 to 132-6 among sounds 132-1 to 132-7 may randomlybe added by the draw, whereas sound 132-7 may be added last withoutfail.

A probability that each of sounds 132 that have not yet been added tosound candidate group 134 is determined as new sound 132 may be equal.Specifically, a probability that each of sounds 132-2, 132-3, 132-4, and132-7 shown in FIG. 8 is determined as a new sound to be added to soundcandidate group 134 may be equal.

A probability of determination as a new sound to be added to soundcandidate group 134 may be different based on the attribute of oradditional information on sound 132.

FIG. 9 is a flowchart showing a processing procedure in the soundaddition processing according to the present embodiment. Each step shownin FIG. 9 is typically performed by execution of system program 108 byprocessor 102 of output apparatus 100.

Referring to FIG. 9 , output apparatus 100 obtains the result ofmeasurement by the sensor that measures body motion of the user (stepS100) and estimates the sleep state of the user (step S102). Outputapparatus 100 determines whether or not the estimated sleep state (depthof sleep) of the user exceeds a prescribed criterion value (step S104).

When the estimated sleep state (depth of sleep) of the user exceeds theprescribed criterion value (YES in step S104), output apparatus 100increments the cumulative total of the hours of sleep of the user (stepS106). When the estimated sleep state (depth of sleep) of the user doesnot exceed the prescribed criterion value (NO in step S104), processingin step S106 is skipped.

Then, output apparatus 100 determines whether or not a condition forstarting determination as to sound addition has been satisfied (stepS108). For example, when the output apparatus can determine that theuser has sufficiently been awake from the sleep state of the user, thecondition for starting determination as to sound addition is satisfied.

When the condition for starting determination as to sound addition hasnot been satisfied (NO in step S108), subsequent processing is skippedand processing in step S100 or later is repeated.

When the condition for starting determination as to sound addition hasbeen satisfied (YES in step S108), output apparatus 100 determineswhether or not the cumulative total of the hours of sleep of the userhas reached at least one of threshold values defined in threshold valuetable 170 (step S110). When the cumulative total of the hours of sleepof the user has reached none of the threshold values defined inthreshold value table 170 (NO in step S110), subsequent processing isskipped and processing in step S100 or later is repeated.

When the cumulative total of the hours of sleep of the user has reachedat least one of threshold values defined in threshold value table 170(YES in step S110), output apparatus 100 extracts sounds 132 that havenot yet been added to sound candidate group 134 (step S112) anddetermines sound 132 to be added among extracted sounds (step S114).Then, output apparatus 100 adds determined sound 132 to sound candidategroup 134 (step S116). Then, processing in step S100 or later isrepeated.

(f2: Determination as to Activation of Sound Addition Processing)

In the processing procedure shown in FIG. 9 , though an example in whichprocessing for adding a sound is performed when the cumulative total ofthe hours of sleep of the user has reached at least one of the thresholdvalues defined in threshold value table 170 is shown, whether or not toperform processing for adding a sound may also be determined by a draw.

Specifically, output apparatus 100 may perform processing fordetermining whether or not to activate processing for adding new sound132 to sound candidate group 134 based on the calculated hours of sleepof the user. In this case, sound 132 is added to sound candidate group134 only when processing for adding new sound 132 is activated.

FIG. 10 is a flowchart showing another processing procedure in the soundaddition processing according to the present embodiment. As comparedwith the flowchart shown in FIG. 9 , the flowchart shown in FIG. 10additionally includes step S120 performed after step S110.

Specifically, when the cumulative total of the hours of sleep of theuser has reached at least one of the threshold values defined inthreshold value table 170 (YES in step S110), output apparatus 100determines whether or not to activate processing for adding new sound132 to sound candidate group 134 (step S120). Determination in step S120may be made based on a length of the hours of sleep of the user during aprescribed most recent period or the cumulative total of the hours ofsleep of the user, or alternatively by the draw. A probability in thedraw may be varied based on the hours of sleep of the user. For example,the probability of activation (that is, the probability of permission)may be higher as the hours of sleep of the user are longer.

When it is determined to activate the processing for adding new sound132 to sound candidate group 134 (YES in step S120), output apparatus100 performs processing in step S112 or later. When it is determined notto activate the processing for adding new sound 132 to sound candidategroup 134 (NO in step S120), subsequent processing is skipped andprocessing in step S100 or later is repeated.

Thus, when the processing for adding a new sound is activated, additionmodule 154 of output apparatus 100 adds new sound 132 to sound candidategroup 134.

(f3: Exemplary Evaluation of Hours of Sleep of User)

Though an example in which the cumulative total of the hours of sleep ofthe user is used is mainly described above, without being limited assuch, the “hours of sleep of the user” may be used in any manner in theprocessing for adding new sound 132 to sound candidate group 134.

For example, a point may be calculated based on hours of sleep for eachprescribed period (for example, twenty-four hours or one week), and whenthe cumulative total of calculated points reaches a prescribed thresholdvalue, new sound 132 may be added to sound candidate group 134.

More specifically, a point can be given in such a manner that, based ona length of the hours of sleep for each night, two points are given whenthe hours of sleep of the user are long, one point is given when thehours of sleep of the user are normal, and zero point is given when thehours of sleep of the user are short. The point may be given every nightor in a unit of a week or a month.

When the cumulative total of points is used, instead of or in additionto processing in steps S106 and S110 shown in FIG. 9 , processing fordetermining a point, processing for calculating the cumulative total ofpoints, and processing for determining whether or not the cumulativetotal of points has reached a prescribed threshold value are performed.

Step S120 shown in FIG. 10 may be performed using points calculatedbased on the hours of sleep for each prescribed period. Specifically,whether or not to activate the processing for adding new sound 132 tosound candidate group 134 may be determined based on the calculatedpoints.

Output apparatus 100 may thus perform an evaluation function after theuser wakes up (gets up), to make an evaluation based on the calculatedhours of sleep immediately before. The “hours of sleep immediatelybefore” means time spent for one sleep (normally, sleep for one night)from determination that the user fell asleep until the user wakes up.Though the sleep may become shallow or the user may be awakened withinone sleep, such a case is handled as one sleep in principle.

By making an evaluation after the user wakes up based on the hours ofsleep immediately before, the hours of sleep of the user cansubstantially be evaluated every day. Addition module 154 of outputapparatus 100 adds new sound 132 to sound candidate group 134 based on aresult of evaluation with the evaluation function.

Processing for evaluating the hours of sleep of the user for eachprescribed period described above can be adopted instead of or togetherwith the processing using the cumulative total of the hours of sleep ofthe user.

G. Sound Selection and Output Processing

Details of the sound selection and output processing will now bedescribed.

As described with reference to FIG. 4 , in the sound selection andoutput processing, sound 132 to be outputted is selected from soundcandidate group 134. Then, the selected sound is outputted.

(g1: Processing Procedure)

FIG. 11 is a flowchart showing a processing procedure in the soundselection and output processing according to the present embodiment.Each step shown in FIG. 11 is typically performed by execution of systemprogram 108 by processor 102 of output apparatus 100.

Referring to FIG. 11 , output apparatus 100 determines whether or notthe output condition has been satisfied (step S200). When the outputcondition has not been satisfied (NO in step S200), processing in stepS200 is repeated.

The output condition typically means arrival of start time set inadvance by the user (that is, set time to get up). When the user's sleepis shallow at the time when start time set in advance is close, theoutput condition may be determined as being satisfied.

When the output condition has been satisfied (YES in step S200), outputapparatus 100 calculates hours of sleep of the user during a prescribedperiod before the output condition is satisfied (step S202).

The hours of sleep of the user during the prescribed period before theoutput condition is satisfied are counted based on the result ofmeasurement by acceleration sensor 112. Therefore, the prescribed periodmay be, for example, a period until twelve hours before the set starttime or a period from timing of determination that the user fell asleepuntil the start time.

Output apparatus 100 makes an evaluation based on the hours of sleep inthe present sleep based on the calculated hours of sleep of the userduring the prescribed period (step S204). For example, the hours ofsleep of the user can be categorized into three types of “long”,“normal”, and “short”. Processing in step S204 is performed as necessaryand may be skipped as appropriate.

Then, output apparatus 100 determines selectable sounds 132 to beincluded in sound candidate group 134 (step S206). At this time, only atleast one sound 132 to be included in sound candidate group 134 may beextracted as a choice based on the length of the hours of sleep in thepresent sleep. By thus changing the choices, as the hours of sleep arelonger, a larger number of sounds 132 can be controlled to be thechoices.

Output apparatus 100 selects sound 132 to be outputted from amongselectable sounds 132 (step S208). Then, output apparatus 100 outputsselected sound 132 from sound generator 118 (step S210). Sound data 130corresponding to selected sound 132 may repeatedly be reproduced.

After sound 132 is outputted, output apparatus 100 determines whether ornot it has received an operation by the user for temporarily stoppingoutput of sound 132 (step S212). The operation by the user fortemporarily stopping output of sound 132 is, for example, an operationto activate a function referred to as snooze.

When output apparatus 100 receives the operation by the user fortemporarily stopping output of sound 132 (YES in step S212), ittemporarily stops output of sound 132 (step S214). Then, outputapparatus 100 stands by for a prescribed period after output of sound132 is temporarily stopped (step S216).

After stand-by for the prescribed period, output apparatus 100 outputsagain sound 132 from sound generator 118 (step S218). When another sound132 is included in the sound set to which currently selected sound 132belongs, selection may be changed to select another sound 132.

Then, output apparatus 100 determines whether or not a condition forquitting output of sound 132 has been satisfied (step S220). When thecondition for quitting output of sound 132 has not been satisfied (NO instep S220), processing in step S212 or later is repeated. When thecondition for quitting output of sound 132 has been satisfied (YES instep S220), the process ends.

When output apparatus 100 has not received the operation by the user fortemporarily stopping output of sound 132 (NO in step S212), itdetermines whether or not a condition for switching sound 132 has beensatisfied (step S222). For example, when a duration of output ofcurrently outputted sound 132 reaches a prescribed duration, the outputapparatus may determine that the condition for switching sound 132 hasbeen satisfied.

When the condition for switching sound 132 has been satisfied (YES instep S222), output apparatus 100 changes its selection to select anothersound 132 included in the sound set to which currently selected sound132 belongs (step S224) and outputs again changed sound 132 from soundgenerator 118 (step S226). Then, processing in step S220 is performed.Unless a plurality of sounds 132 are included in the sound set to whichcurrently selected sound 132 belongs even when the condition forswitching sound 132 has been satisfied, processing in steps S224 andS226 is skipped.

When the condition for switching sound 132 has not been satisfied (NO instep S222), processing in steps S224 and S226 is skipped.

In the processing procedure shown in FIG. 11 , though exemplaryprocessing for starting selection of sound 132 to be outputted when acondition for starting output of sound 132 (output condition) issatisfied is shown, the condition for starting output of sound 132 andthe condition for starting selection of sound 132 may be setindependently of each other. In other words, since sound 132 to beoutputted should only be selected before start of processing foroutputting sound 132, timing to select sound 132 may freely bedetermined.

(g2: Determination of Selectable Sounds (S206))

In a method of determining selectable sounds 132 in the processingprocedure shown in FIG. 11 , all sounds 132 that have been added tosound candidate group 134 may be set as choices.

Alternatively, only at least one sound 132 of sounds 132 that have beenadded to sound candidate group 134 may be set as a choice based on anyinformation.

FIG. 12 is a schematic diagram for illustrating an exemplary method ofdetermining selectable sounds 132 in output apparatus 100 according tothe present embodiment. Referring to FIG. 12 , sound management table140 includes information as to whether or not a sound can be a choice(which is also referred to a “choice attribute” below) in addition toinformation on prepared sounds 132-1 to 132-7 and information as towhether or not each sound 132 has already been added to sound candidategroup 134.

More specifically, sound management table 140 includes a choiceattribute 136-1 when the hours of sleep in the present sleep are “long”,a choice attribute 136-2 when the hours of sleep in the present sleepare “normal”, and a choice attribute 136-3 when the hours of sleep inthe present sleep are “short”.

In an example shown in FIG. 12 , selectable sounds 132 when the hours ofsleep are “normal” are a subset of selectable sounds 132 when the hoursof sleep are “long”, and selectable sounds 132 when the hours of sleepare “short” are a subset of selectable sounds 132 when the hours ofsleep are “long” and a subset of selectable sounds 132 when the hours ofsleep are “normal”. By adopting such relation of a set, the number ofselectable sounds 132 when the hours of sleep are “long” can reliably belarger than the number of selectable sounds 132 when the hours of sleepare “normal” and “short”. Such relation of a subset does not necessarilyhave to be maintained.

Output apparatus 100 makes an evaluation based on the hours of sleep inthe present sleep (see step S204 in FIG. 11 ) and determines selectablesounds 132 by referring to choice attribute 136 corresponding to aresult of evaluation.

Thus, when the calculated hours of sleep of the user exceed prescribedhours, sound selection module 158 of output apparatus 100 may selectsound 132 to be outputted from among a larger number of sounds than whenthe calculated hours of sleep of the user do not exceed the prescribedhours.

(g3: Selection of Sound (S208))

In a method of selecting sound 132 in the processing procedure shown inFIG. 11 , sound 132 to be outputted may be selected from amongselectable sounds 132 in a predetermined order. Specifically, soundselection module 158 of output apparatus 100 may select sound 132 to beoutputted in a predetermined order based on identifiers or the like ofselectable sounds 132. By adopting such a method, the user can hear allsounds 132 included in sound candidate group 134.

A method of selecting sound 132 to be outputted from among selectablesounds 132 by the draw may be adopted as another method of selectingsound 132 to be outputted. Specifically, sound selection module 158 ofoutput apparatus 100 selects sound 132 to be outputted from amongselectable sounds 132 by the draw. By adopting such a method, the usercan be given unexpectedness.

At this time, the probability of selection of sound 132 may be variedbased on a result of evaluation based on the hours of sleep in thepresent sleep.

FIG. 13 is a schematic diagram for illustrating an exemplary method ofselecting sound 132 in output apparatus 100 according to the presentembodiment. Referring to FIG. 13 , sound management table 140 includesinformation representing a probability of selection (which is alsoreferred to a “selection probability setting” below) in addition toinformation on prepared sounds 132-1 to 132-7 and information as towhether or not each sound 132 has already been added to sound candidategroup 134.

More specifically, sound management table 140 includes a selectionprobability setting 138-1 when the result of evaluation of the hours ofsleep in the present sleep indicates “long”, a selection probabilitysetting 138-2 when the result of evaluation of the hours of sleep in thepresent sleep indicates “normal”, and a selection probability setting138-3 when the result of evaluation of the hours of sleep in the presentsleep indicates “short”. A value shown in selection probability setting138 is a kind of a weight coefficient, and a larger value means a higherprobability of selection.

In each of selection probability settings 138, the probability set foreach sound 132 is not equal. For example, in selection probabilitysetting 138-1, a higher probability of selection is set for “fine_1” and“fine_2” than other sounds 132 (mood). In selection probability setting138-3, a higher probability is set for “grumpy_1”, “grumpy_2”,“sleepy_1”, and “sleepy_2” than other sounds 132 (mood).

The probability that at least one sound 132 included in sound candidategroup 134 is selected as sound 132 to be outputted may be different fromthe probability that another sound 132 included in sound candidate group134 is selected as sound 132 to be outputted.

Output apparatus 100 makes an evaluation based on the hours of sleep inthe present sleep (see step S204 in FIG. 11 ) and determines theprobability of selection of each sound 132 included as the choice byreferring to selection probability setting 138 corresponding to theresult of evaluation. Then, output apparatus 100 selects sound 132 to beoutputted by the draw, based on the determined probability of selectionof each sound 132.

The probability (selection probability setting 138) that sound 132included in sound candidate group 134 is selected as sound 132 to beoutputted by the draw may thus be higher as the hours of sleep of theuser during the prescribed period before the output condition issatisfied are longer.

In changing selectable sound 132 among sounds 132 included in soundcandidate group 134 as shown in FIG. 12 , by setting the probability ofcorresponding sound 132 in selection probability setting 138 shown inFIG. 13 to “zero”, substantially the same result may be obtained.

FIG. 14 is a schematic diagram for illustrating another exemplary methodof selecting sound 132 in output apparatus 100 according to the presentembodiment. Referring to FIG. 14 , the probability of sound 132 to beexcluded from choices in each of selection probability settings 138-1,138-2, and 138-3 is set to “zero”. By adopting such selectionprobability setting 138, the choices can be different and theprobability of selection of each sound 132 can also be differentdepending on the length of the hours of sleep in the present sleep.

In addition to setting of the probability of selection in advance forsound 132, the probability of selection may dynamically be varied. Forexample, selection of sound 132 shortly after addition thereof to soundcandidate group 134 may be more likely. Specifically, sound 132 morerecently added to sound candidate group 134 may be higher in probabilityof selection as sound 132 to be outputted. Furthermore, immediatelyafter addition of new sound 132, that added new sound 132 may beselected without fail.

By thus setting the probability of selection, possibility that the userhears sound 132 soon after addition thereof to sound candidate group 134can be made higher.

(g4: Change of Sound (S218 and S226))

Processing for changing the sound (S218 and S226) in the processingprocedure shown in FIG. 11 will now be described.

FIG. 15 is a schematic diagram for illustrating exemplary processing forchanging a sound in output apparatus 100 according to the presentembodiment. Referring to FIG. 15 , sounds 132 are added to soundcandidate group 134 in a unit of a sound set 133 composed of a pluralityof sounds 132.

In an example shown in FIG. 15 , a sound set 133-1 composed of sound132-1 is associated with the mood “fawning.” A sound set 133-2 composedof sounds 132-2A, 132-2B, and 132-2C is associated with the mood“fine_1”. A sound set 133-3 composed of sounds 132-3A and 132-3B isassociated with the mood “fine_2”. A sound set 133-4 composed of sounds132-4A, 132-4B, and 132-4C is associated with the mood “grumpy_1”.

Sounds 132 to be outputted are thus selected in a unit of sound set 133from sound candidate group 134 shown in FIG. 15 . Then, at least one ofone or more sounds 132 included in selected sound set 133 is outputted.Specifically, sound selection module 158 of output apparatus 100 selectssounds 132 to be outputted in a unit of sound set 133 and determinessound 132 to be outputted from among sounds 132 included in selectedsound set 133.

When sound set 133 includes a plurality of sounds 132, output apparatus100 switches among sounds 132 to be outputted as appropriate in responseto any switching condition being satisfied.

For example, when sound set 133 corresponding to “fine_1” has beenselected, initially, a voice (sound 132-2A) for waking the user up isoutputted in a tone giving a “fine” impression. When the switchingcondition is satisfied after output of sound 132-2A, switching to avoice (sound 132-2B) for waking the user up in a slightly forceful toneis made. Furthermore, when the switching condition is satisfied afteroutput of sound 132-2B, switching to a voice (sound 132-2C) for wakingthe user up in a more forceful tone is made.

When the switching condition is satisfied after output of sound 132 isstarted, sound selection module 158 of output apparatus 100 thus selectssound 132 different from previously selected sound 132 as sound 132 tobe outputted next, from among sounds 132 included in selected sound set133.

The duration of output of currently outputted sound 132 reaching aprescribed duration may be adopted as the condition for switching sound132 (step S224 in FIG. 11 ). Specifically, when output of sound 132 isnot temporarily stopped (NO in S212 in FIG. 11 ), output of sound 132continues. When the duration of output of sound 132 that is being outputreaches the prescribed duration (for example, three minutes), a type ofsound 132 to be outputted may be changed.

When a duration of reproduction of sound 132 is, for example,approximately several seconds, in order to continue output of sound 132,the same sound 132 is repeatedly reproduced. The number of times ofrepetition of this same sound 132 reaching a predetermined number oftimes may be set as the condition for switching of sound 132.

Temporary stop of output of sound 132 may be adopted as anothercondition for switching of sound 132. Output apparatus 100 may be ableto temporarily stop output of sound 132 in response to an operation bythe user (S212 and S214 in FIG. 11 ). In this case, the type of sound132 to be outputted may be changed by being triggered by temporary stopof output of sound 132. Since output of sound 132 has temporarily beenstopped, changed sound 132 is not actually outputted until a prescribedtime period elapses and the output condition is satisfied again.

H. Processing for Output Again of Sound

Processing for outputting again previously outputted sound 132 will nowbe described.

FIG. 16 is a flowchart showing a processing procedure for output againof a sound according to the present embodiment. Each step shown in FIG.16 is typically performed by execution of system program 108 byprocessor 102 of output apparatus 100.

Referring to FIG. 16 , output apparatus 100 determines whether or not acondition for output again of sound 132 has been satisfied (step S300).When the condition for output again of sound 132 has not been satisfied(NO in step S300), processing in step S300 or later is repeated.

When the condition for output again of sound 132 has been satisfied (YESin step S300), output apparatus 100 determines whether or not timeelapsed since end of most recent output of sound 132 is equal to orshorter than a prescribed period (step S302). When time elapsed sinceend of most recent output of sound 132 is longer than the prescribedperiod (NO in step S300), processing in step S300 or later is repeated.

When the time elapsed since end of most recent output of sound 132 isequal to or shorter than the prescribed period (YES in step S302),output apparatus 100 outputs sound 132, output of which has ended, fromsound generator 118 (step S304). In step S304, basically, sound data 130corresponding to sound 132, output of which has ended, is reproducedonce. Then, processing in step S300 or later is performed.

When the condition for output again is satisfied within the prescribedperiod after end of output of sound 132, sound output module 160 ofoutput apparatus 100 outputs again sound 132, output of which has ended.

Reception of an operation by the user may be adopted as the conditionfor output again. Specifically, reception of an operation by the useronto operation unit 122 of output apparatus 100 or shaking of outputapparatus 100 by the user may be adopted as the condition for outputagain.

For example, a shake that occurs in output apparatus 100 can be sensedbased on a result of measurement from acceleration sensor 112. Thecondition for output again may thus include sensing of a shake of outputapparatus 100.

I. Other Embodiments

Though an exemplary configuration for output of a sound has beendescribed, light or vibration may be outputted in addition to or insteadof the sound. In this case as well, similarly to the sound, variation ofoutputted light or vibration may sequentially be added.

While certain example systems, methods, devices and apparatuses havebeen described herein, it is to be understood that the appended claimsare not to be limited to the systems, methods, devices and apparatusesdisclosed, but on the contrary, are intended to cover variousmodifications and equivalent arrangements included within the spirit andscope of the appended claims.

What is claimed is:
 1. An information processing apparatus comprising: amemory storing a computer-readable program; and one or more processors,when executing the computer-readable program, that perform selecting asound to be outputted from a sound candidate group, outputting theselected sound when an output condition is satisfied, estimating a sleepstate of a user based on a result of measurement by a sensor thatmeasures body motion of the user, calculating hours of sleep of the userbased on the estimated sleep state of the user, and adding a new soundto the sound candidate group based on the calculated hours of sleep ofthe user.
 2. The information processing apparatus according to claim 1,wherein the adding the new sound to the sound candidate group is basedon a cumulative total of the calculated hours of sleep of the user. 3.The information processing apparatus according to claim 2, wherein theadding the new sound to the sound candidate group comprises adding thenew sound when the cumulative total of the calculated hours of sleep ofthe user reaches a prescribed threshold value.
 4. The informationprocessing apparatus according to claim 3, wherein the prescribedthreshold value comprises a plurality of threshold values, and theadding the new sound to the sound candidate group comprises adding thenew sound each time the cumulative total of the calculated hours ofsleep of the user reaches a threshold value of the plurality ofthreshold values.
 5. The information processing apparatus according toclaim 4, wherein as compared with a difference between a first thresholdvalue included in the plurality of threshold values and a secondthreshold value largest next to the first threshold value, a differencebetween the second threshold value and a third threshold value largestnext to the second threshold value is larger.
 6. The informationprocessing apparatus according to claim 1, wherein the one or moreprocessors, when executing the computer-readable program, furtherperform, after the user wakes up, evaluation based on the calculatedhours of sleep immediately before, and the adding the new sound to thesound candidate group comprises adding the new sound based on a resultof the evaluation.
 7. The information processing apparatus according toclaim 1, wherein the adding the new sound to the sound candidate groupcomprises determining the new sound to be added by a draw.
 8. Theinformation processing apparatus according to claim 7, wherein aprobability that each of sounds that have not yet been added to thesound candidate group is determined as the new sound is equal.
 9. Theinformation processing apparatus according to claim 1, wherein the oneor more processors, when executing the computer-readable program,further perform determining whether to activate processing for adding anew sound to the sound candidate group based on the calculated hours ofsleep of the user, and the adding the new sound to the sound candidategroup comprises adding the new sound to the sound candidate group whenprocessing for adding the new sound is activated.
 10. The informationprocessing apparatus according to claim 1, wherein the selecting a soundcomprises selecting a sound to be outputted from the sound candidategroup by a draw.
 11. The information processing apparatus according toclaim 10, wherein the one or more processors, when executing thecomputer-readable program, further perform determining one or moreselectable sounds from sounds included in the sound candidate groupbased on the hours of sleep of the user immediately before the outputcondition is satisfied.
 12. The information processing apparatusaccording to claim 11, wherein the selecting the sound comprisesselecting, when the calculated hours of sleep of the user exceedprescribed hours, a sound to be outputted from among more sounds thanwhen the calculated hours of sleep of the user do not exceed theprescribed hours.
 13. The information processing apparatus according toclaim 11, wherein a probability that at least one sound included in thesound candidate group is selected as the sound to be outputted is higheras the hours of sleep of the user are longer.
 14. The informationprocessing apparatus according to claim 11, wherein a probability thateach of sounds included in the sound candidate group is selected as thesound to be outputted is equal.
 15. The information processing apparatusaccording to claim 11, wherein a sound more recently added to the soundcandidate group is higher in probability of selection as the sound to beoutputted.
 16. The information processing apparatus according to claim1, wherein the selecting a sound comprises selecting the sound to beoutputted in a predetermined order from the sound candidate group. 17.The information processing apparatus according to claim 1, wherein asound is added to the sound candidate group in a unit of a sound setcomposed of a plurality of sounds, and the selecting a sound comprisesselecting sounds to be outputted in the unit of the sound set anddetermining a sound to be outputted from among the sounds included inthe selected sound set.
 18. The information processing apparatusaccording to claim 17, wherein the selecting the sound comprisesselecting as a sound to be outputted next, a sound different from apreviously selected sound from among the sounds included in the soundset when a switching condition is satisfied after output of the sound isstarted.
 19. The information processing apparatus according to claim 18,wherein the switching condition comprises a condition that a duration ofoutput of a sound that is currently being outputted reaches a prescribedduration.
 20. The information processing apparatus according to claim18, wherein the one or more processors, when executing thecomputer-readable program, further perform temporarily stopping outputof the sound, and the switching condition comprises temporary stop ofoutput of the sound.
 21. The information processing apparatus accordingto claim 1, wherein the outputting the sound comprises outputting againthe sound, output of which has ended, when a condition for output againis satisfied within a prescribed period after end of output of thesound.
 22. The information processing apparatus according to claim 21,wherein the one or more processors, when executing the computer-readableprogram, further perform sensing a shake that occurs in the informationprocessing apparatus, and the condition for output again comprisessensing of the shake of the information processing apparatus.
 23. Theinformation processing apparatus according to claim 1, wherein thesensor comprises an acceleration sensor.
 24. The information processingapparatus according to claim 1, wherein the one or more processors, whenexecuting the computer-readable program, further perform obtaining asound from another information processing apparatus different from theinformation processing apparatus.
 25. A system including a soundgenerator, the system comprising: a sound selection module that selectsa sound to be outputted from a sound candidate group; a sound outputmodule that outputs the selected sound from the sound generator when anoutput condition is satisfied; a sleep state estimation module thatestimates a sleep state of a user based on a result of measurement by asensor that measures body motion of the user; an hours-of-sleepcalculation module that calculates hours of sleep of the user based onthe estimated sleep state of the user; and an addition module that addsa new sound to the sound candidate group based on the calculated hoursof sleep of the user.
 26. A non-transitory computer-readable storagemedium with an executable program stored thereon, the program causing acomputer configured to output a sound to perform: selecting a sound tobe outputted from a sound candidate group; outputting the selected soundwhen an output condition is satisfied; estimating a sleep state of auser based on a result of measurement by a sensor that measures bodymotion of the user; calculating hours of sleep of the user based on theestimated sleep state of the user; and adding a new sound to the soundcandidate group based on the calculated hours of sleep of the user. 27.A method performed in an information processing apparatus configured tooutput a sound, the method comprising: selecting a sound to be outputtedfrom a sound candidate group; outputting the selected sound when anoutput condition is satisfied; estimating a sleep state of a user basedon a result of measurement by a sensor that measures body motion of theuser; calculating hours of sleep of the user based on the estimatedsleep state of the user; and adding a new sound to the sound candidategroup based on the calculated hours of sleep of the user.